Capacitative calcium entry in smooth muscle cells from preglomerular vessels.
Capacitative calcium entry in smooth muscle cells from preglomerular vessels.
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DOI：
10.1152/ajprenal.1999.277.4.f533
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发表时间：
1999-10
期刊：
影响因子：
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通讯作者：
S. Fellner;W. Arendshorst
中科院分区：
文献类型：
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作者：
S. Fellner;W. Arendshorst
激动剂刺激后传入小动脉中胞浆钙 ([Ca2+]i) 增加的至少一半是通过电压门控 L 型通道进入的钙造成的。我们寻找来自大鼠肾小球前血管的新鲜血管平滑肌细胞（VSMC）中是否存在电容性钙进入。 [Ca2+]i 使用 fura-2 比率荧光进行测量。加压素 V1 受体激动剂 (V1R) (10-7M) 使 [Ca2+]i 增加约 100 nM。钙通道阻滞剂 (CCB)、硝苯地平或维拉帕米 (10-7 M) 可抑制反应约 50%。 CCB 存在下的 V1R 将 [Ca2+]i 从 106 nM 增加至 176 nM，证实钙动员和/或进入可能独立于电压门控通道而发生。在名义上不含 Ca2+ 的缓冲液中，V1R 将 [Ca2+]i 从 94 nM 增加至 129 nM，表示动员；添加 CaCl2 (1 mM) 进一步升高 [Ca2+] 至 176 nM，表明 Ca2+ 进入的第二阶段。当 CCB 存在于无钙缓冲液中或存在 EGTA 时，获得了类似的反应。在名义上不含 Ca2+ 的培养基中，当添加 1 mM 细胞外 Ca2+ 时，肌浆网 Ca2+-ATP 酶抑制剂 (SRCAI)、毒胡萝卜素和环吡阿尼酸 (CPA) 将 [Ca2+]i 分别从 97 增加至 128 和 143 nM，并分别增加至 214 和 220 nM。在维拉帕米存在的情况下，CPA 酸的结果几乎相同。在不含 Ca2+ 的缓冲液中，V1R 或 SRAI 对 Ca2+/fura 信号的刺激作用通过添加 Mn2+ (1 mM) 被淬灭，表明二价阳离子进入。这些研究为从大鼠肾小球前小动脉中新鲜分离的 VSMC 中的电容性（存储操作）钙进入提供了证据。
Calcium entry via voltage-gated L-type channels is responsible for at least half of the increase in cytosolic calcium ([Ca2+]i) in afferent arterioles following agonist stimulation. We sought the presence of capacitative calcium entry in fresh vascular smooth muscle cells (VSMC) derived from rat preglomerular vessels. [Ca2+]iwas measured using fura-2 ratiometric fluorescence. Vasopressin V1 receptor agonist (V1R) (10-7M) increased [Ca2+]iby ∼100 nM. A calcium channel blocker (CCB), nifedipine or verapamil (10-7 M), inhibited the response by ∼50%. V1R in the presence of CCB increased [Ca2+]ifrom 106 to 176 nM, confirming that calcium mobilization and/or entry may occur independent of voltage-gated channels. In nominally Ca2+-free buffer, V1R increased [Ca2+]ifrom 94 to 129 nM, denoting mobilization; addition of CaCl2 (1 mM) further elevated [Ca2+]ito 176 nM, indicating a secondary phase of Ca2+ entry. Similar responses were obtained when CCB was present in calcium-free buffer or when EGTA was present. In nominally Ca2+-free medium, the sarcoplasmic reticulum Ca2+-ATPase inhibitors (SRCAI), thapsigargin and cyclopiazonic acid (CPA), increased [Ca2+]ifrom 97 to 128 and 143 nM, respectively, and to 214 and 220 nM, respectively, when 1 mM extracellular Ca2+ was added. In the presence of verapamil, the results with CPA acid were nearly identical. In Ca2+-free buffer, the stimulatory effect of V1R or SRCAI on the Ca2+/fura signal was quenched by the addition of Mn2+ (1 mM), demonstrating divalent cation entry. These studies provide evidence for capacitative (store- operated) calcium entry in VSMC freshly isolated from rat preglomerular arterioles.